1. Field of the Invention
This invention relates to a method of generating a set of test sequences to confirm proper operation of interconnected communication systems.
2. Discussion of the Known Art
Generation of test sequences to determine whether or not a given communication system conforms to a specification or design requirement, is common practice. Automated test equipment available on the market is usually rented or leased by a system operator to test a system for proper operation when necessary. Such equipment is typically configured to perform a number of key tests in accordance with a program written specifically for the system.
It is believed that Internet protocol (IP) will play a large, if not dominant, role in future public telephony networks. Such networks are expected to handle not only voice, but video and other information and data as well. It is therefore important that existing data-centric and public switched telephone networks (PSTNs) be capable of operation when connected with one another through so-called “gateways”. The ability of such networks or systems to operate properly when inter-connected is typically referred to as system “interoperability”.
With respect to providing voice calls over an IP network (“Voice over IP” or “VoIP”), the first VoIP systems provided voice communications over a local area network (LAN) for end-users seated at personal computers. This proved unsatisfactory for several reasons. For example, voice quality was poor due to a “best-effort” standard for data packet delivery in the LAN environment. Also, there was no way to direct a voice call to a user connected to a PSTN, thus limiting the number of possible calls. And, a called end-user PC might not be connected to the network when the call was placed.
Because some providers believed IP telephony might circumvent long distance user rates due to the absence of tariffs on local Internet access, local user access gateways to PSTNs were created in each locality to be served, with a private Internet providing a long-distance backbone for voice calls. LEC's became interested in a similar strategy, but instead of using a gateway to connect local lines to an IP network, gateways were used to connect their central offices to an IP network, thus replacing a circuit-switched network backbone with an IP network. Finally, corporations maintaining large data networks became interested in combining their voice and data networks by running Voice over IP.
In view of the above, the existing diversity of VoIP implementations results in diverse communications systems that may not be able to interoperate when connected together. In order for these existing communication systems to remain effective, they must be able to interwork with the PSTN and with other VoIP products.